Thirty experienced male swimmers with body types ± 1 SD of the mean of selected body form parameters reported for elite male swimmers were recruited for the study. During three freestyle flip turns, selected kinetic, hydrodynamic, and kinematic variables of the push-off following a flip turn were recorded. Kinetics were recorded via a 2D vertically mounted forceplate that recorded peak push-off force and total impulse. The acceleration of each swimmer’s center of gravity and wall exit velocity were calculated from underwater videography. Hydrodynamic peak drag force and drag impulse were calculated from the kinetic and kinematic data using a derivative of Newton’s second law. A stepwise regression yielded peak drag force, peak propulsive force, and push-off time in the final regression equation (R = 0.80; R 2 = 0.64). Beta values indicated that the peak drag force carried the highest weighting of the three variables. The results of the stepwise regression indicated that a combination of a low peak drag force high peak propulsive force, and increased wall push-off time produced the fastest final push-off velocity.
Search Results
Investigating Kinetics in the Freestyle Flip Turn Push-Off
Andrew D. Lyttle, Brian A. Blanksby, Bruce C. Elliott, and David G. Lloyd
Persons With Multiple Sclerosis Show Altered Joint Kinetics During Walking After Participating in Elliptical Exercise
Jessie M. Huisinga, Kendra K. Schmid, Mary L. Filipi, and Nicholas Stergiou
Patients with multiple sclerosis (MS) experience abnormal gait patterns and reduced physical activity. The purpose of this study was to determine if an elliptical exercise intervention for patients with MS would change joint kinetics during gait toward healthy control values. Gait analysis was performed on patients with MS (n = 24) before and after completion of 15 sessions of supervised exercise. Joint torques and powers were calculated, while also using walking velocity as a covariate, to determine the effects of elliptical exercise on lower extremity joint kinetics during gait. Results show that elliptical exercise significantly altered joint torques at the ankle and hip and joint powers at the ankle during stance. The change in joint power at the ankle indicates that, after training, patients with MS employed a walking strategy that is more similar to that of healthy young adults. These results support the use of elliptical exercise as a gait training tool for patients with MS.
Kinetics of Crimp and Slope Grip in Rock Climbing
Andreas Schweizer and Robert Hudek
The aim was to investigate differences of the kinetics of the crimp and the slope grip used in rock climbing. Nine cadaver fingers were prepared and fixated with the proximal phalanx in a frame. The superficial (FDS) and deep (FDP) flexor tendons were loaded selectively and together with 40 N in the crimp grip (PIP joint flexed 90°/DIP joint hyperextended) and the slope grip position (<25° flexed/50° flexed respectively). Five different grip sizes were tested and the flexion force which was generated to the grip was measured. In the crimp grip the FDP generated more flexion force in small sized holds whereas the FDS generated more force in the larger holds. During the slope grip the FDP was more effective than the FDS. While both tendons were loaded, the flexion force was always greater during crimp grip compared with the slope grip. The FDP seems to be most important for very small holds using the crimp grip but also during slope grip holds whereas the FDS is more important for larger flat holds.
The Relationship Between Vertical Ground Reaction Force, Loading Rate, and Sound Characteristics During a Single-Leg Landing
Caroline Lisee, Tom Birchmeier, Arthur Yan, Brent Geers, Kaitlin O’Hagan, Callum Davis, and Christopher Kuenze
improving their movement quality and reduce subsequent injury risk. 3 Unfortunately, these attempts to evaluate and intervene to improve movement patterns have significant shortcomings as they fail to consider the role that kinetics, such as loading characteristics, play in the risk of primary or secondary
The Kinetics of Swinging a Baseball Bat
Joseph J. Crisco, Nikolas J. Osvalds, and Michael J. Rainbow
addition, the swing used in the analysis did not hit a baseball. To the best of our knowledge, this was the only study that examined the kinetics of swinging a baseball bat. What effect a bat’s moments of inertia (MOI), swings across multiple batters, and swings of actual batted baseballs have on these
Reducing the Loss of Velocity and Power in Women Athletes via Rest Redistribution
Justin J. Merrigan, James J. Tufano, Jonathan M. Oliver, Jason B. White, Jennifer B. Fields, and Margaret T. Jones
the resistance trained. However, the previously mentioned studies utilized either heavy loads or fatiguing protocols to failure and did not address high-volume training without failure. Therefore, the purpose of this study was to examine the acute effects of RR and TS on back squat kinetics and
Kinetics and Stabilization of the Tuck Jump Assessment
Lucy S. Kember, Rhodri S. Lloyd, Gregory D. Myer, and Isabel S. Moore
sensitivity. Previous research has suggested that kinetics during rebounding tasks can be predictors of ACL injury. 7 , 8 Stiff landings with minimal knee flexion have been shown to produce large vertical ground reaction forces (Fz) and result in high knee joint loads and strain on the ACL, which may
Vertical Finger Displacement Is Reduced in Index Finger Tapping During Repeated Bout Rate Enhancement
Mark Holten Mora-Jensen, Pascal Madeleine, and Ernst Albin Hansen
kinetics of the finger tapping ( Sardroodian, Madeleine, Mora-Jensen, & Hansen, 2016 ). Kinematic and kinetic characteristics of the finger tapping were not measured in our previous study ( Hansen et al., 2015 ). Consequently, knowledge on the effect of repeated bout rate enhancement on such aspects of
Strides to Achieve a Stable Symmetry Index During Running
Shane P. Murphy, Zach B. Barrons, and Jeremy D. Smith
important to emphasize that not all variables reached a SMSI in the same number of strides, with some measures such as joint kinetics and joint angles requiring a greater number of strides (Table 1 ). This discretion between variables may partially be due to how variant the discrete measures are during
Oxygen Uptake Kinetics in Youth: Characteristics, Interpretation, and Application
Melitta A. McNarry
Pulmonary oxygen uptake ( V ˙ O 2 ) kinetics following the onset of constant work rate exercise provides a useful assessment of the integrated capacity of the organism to transport and utilizes O 2 to support the increased rate of energy turnover in the contracting myocytes ( 104 ). The onset of
